Looks like my work trip now includes a day in Singapore on the return leg, arriving 7am and not flying out until 11:45pm. Any experiences on the best way from Changi Airport into town, and any must sees during the day - apart from trying to find a few caches of course

Recommendations on cheap electronic toystores that would be open on a Sunday wouldn't go amiss either

I was in Singapore only a month ago.
There is a tour of Singapore from the airport. Its a bus and you can leave your bags at the airport. I think its free.
The airport is really cool, with good food (once through customs) and free cinemas and internet etc.
There are two places for IT - funan IT mall and SimLim Square. Sim Lim Square is the best as Funan is expensive. SimLim is located near Little India station on the Albert Street mall. You can also get off at Bugis and go through Bugis street mall to get there.
Bugus is a huge mall and good shopping.

The train system in Singapore is very good and you can get a train into the city from the airport terminal. Its pretty easy to get about using trains - we also found that walking was no problem as the city is quite compact.

I endorse boodi's comments re Sim Lim and Funan - a big part of our tip was to allow my son to go shopping and he had a great time in those malls.

We also visited the Museum of Asian Civilisation - really enjoyed it. Even the boy did not begrudge the time out from shopping.

We'll be in Singapore some time around the 23rd February. I will be there for a week or so but my husband will only be there for the weekend. I love Singapore, very excited about showing my husband. Plus this will be the first time I've cached there!